How to perform routine maintenance checks

Daily

bash

systemctl --failed
journalctl -u sshd -p err --since "24 hours ago" --no-pager | tail -50
df -h /
docker ps --format 'table {{.Names}}\t{{.Status}}'

Weekly

bash

systemctl status fstrim.timer --no-pager
apt list --upgradable
sudo dmesg --level=warn | grep -i workqueue | tail -20

Monthly

Reload/restart services that accumulated package updates
Review log volume / journal disk
Test a restic restore to /tmp
Spot-check Fail2Ban bans and UFW rules

Timers of interest: sysstat-collect.timer, fstrim.timer, apt-daily-upgrade.timer, etckeeper.timer, logrotate.timer.